An English MP called Samuel Plimsoll (1824 - 1898) campaigned for many years to make ships safer, and as a result in 1876 Parliament passed a law ordering British ships to have a special line drawn through a circle, the Plimsoll Line, painted on the side. This had to be visible above the water at all times. However, cold water is denser than warm water, and salty water is denser than fresh water, so a ship will float higher in cold or salty water than warm or fresh water. Today therefore ships have to be marked not only with the Plimsoll Line but also with International Load Lines which take this into account. What is the Plimsoll line on a ship line for

A ship never completley floats on water, a part of it is always submerged below the water surface depending upon its weight. The Plimsoll line is a line drawn on the lower end of ships, marking the maximum level to which the ship can sink into water after its tare capacity is full. If the water level goes above the Plimsoll line in the event of overloading or other technical problems, it is considered dangerous as the ship may sink. The original "Plimsoll Mark" was a circle with a horizontal line through it to show the maximum draft of a ship. Additional marks have been added over the years, allowing for different water densities and expected sea conditions. Why do ships have a plimsoll line?To tell how high or low the ship is resting in the water. Also by examining the plimsoll line you can see how heavy a load is that the ship is carrying and is sometimes used as a warning against overloadingWhy is there a plimsoll line The Plimsoll line is there for safety's sake. It's to prevent overloading of a vessel. The Plimsoll line or Plimsoll mark is named for the 19th Century Englishman Samuel Plimsoll, who first suggested that it was necessary to have permanent line or mark on the hull of merchant ships to show the depth to which a vessel may be safely and legally loaded. This "load" line differs from the...